syzbot
kernel:c
Status:
closed as dup on 2026/08/16 00:03
Reported-by: syzbot+9e92a3a69c05329cb48a@syzkaller.appspotmail.com
First crash: 52d, last: 52d
Sample crash report:
Xkernel:c
pageStopped at savectx+0xae: movl $0,%gs:0x688
TID PID UID PRFLAGS PFLAGS CPU COMMAND
454081 57635 0 0 0x4000000 1K syz-executor
*514117 34015 0 0 0 0 syz-executor
savectx() at savectx+0xae
end of kernel
end trace frame: 0x768cf77a8b90, count: 14
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports. Insufficient info makes it difficult to find and fix bugs.
ddb{0}>
ddb{0}> set $lines = 0
ddb{0}> set $maxwidth = 0
ddb{0}> show panic
*cpu1: uvm_fault(0xfffff98068fca3f0, 0x98, 0, 1) -> e
ddb{0}> trace
savectx() at savectx+0xae
end of kernel
end trace frame: 0x768cf77a8b90, count: -1
ddb{0}> show registers
rdi 0
rsi 0
rbp 0xffff80003bbb91c0
rbx 0
rdx 0
rcx 0xffff800045fee7e0
rax 0x3b
r8 0xffff80003bbb90f0
r9 0
r10 0x64d6f1871b1159f7
r11 0x48c750ead18a0f62
r12 0
r13 0
r14 0xffff800045fee7e0
r15 0
rip 0xffffffff825273ee savectx+0xae
cs 0x8
rflags 0x46
rsp 0xffff80003bbb9140
ss 0x10
savectx+0xae: movl $0,%gs:0x688
ddb{0}> show proc
PROC (syz-executor) tid=514117 pid=34015 tcnt=3 stat=onproc
flags process=0 proc=0
runpri=86, usrpri=86, slppri=32, nice=20
wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
forw=0xffffffffffffffff, list=0xffff800045fee2b0,0xffff80003bba6a98
process=0xffff80002a37e698 user=0xffff80003bbb4000, vmspace=0xfffff98068fcad78
estcpu=36, cpticks=2, pctcpu=0.0, user=1, sys=1, intr=0
ddb{0}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
57635 319819 46749 0 2 0 syz-executor
57635 454081 46749 0 7 0x4000000 syz-executor
*34015 514117 33011 0 7 0 syz-executor
34015 37658 33011 0 2 0x4000000 syz-executor
34015 28742 33011 0 3 0x4000080 fsleep syz-executor
63041 87225 21279 0 2 0 syz-executor
63041 433322 21279 0 3 0x4000080 fsleep syz-executor
63041 3528 21279 0 3 0x4000080 fsleep syz-executor
74123 407649 37662 0 2 0 syz-executor
74123 240074 37662 0 3 0x4000080 fsleep syz-executor
5107 193792 53424 0 3 0x1 inode syz-executor
5107 316360 53424 0 3 0x4000080 fsleep syz-executor
77516 246263 0 0 3 0x14200 acct acct
37662 167577 35657 0 3 0x82 nanoslp syz-executor
46749 419995 35657 0 3 0x82 nanoslp syz-executor
33294 254507 35657 0 3 0x82 nanoslp syz-executor
53424 494630 35657 0 3 0x82 nanoslp syz-executor
33011 453287 35657 0 3 0x82 nanoslp syz-executor
24341 500913 35657 0 3 0x82 nanoslp syz-executor
48912 30545 35657 0 3 0x2 biowait syz-executor
21279 436839 35657 0 3 0x82 nanoslp syz-executor
35657 396821 31910 0 3 0x3 inode syz-executor
31910 283485 48218 0 3 0x10008a sigsusp ksh
48218 59832 26476 0 3 0x98 kqread sshd-session
26476 501281 98730 0 3 0x92 kqread sshd-session
98730 91883 1 0 3 0x88 kqread sshd
1669 447491 72566 74 3 0x1100092 bpf pflogd
72566 27438 1 0 3 0x80 sbwait pflogd
81319 247506 78732 73 3 0x1100090 kqread syslogd
78732 331373 1 0 3 0x100082 sbwait syslogd
25069 158972 1 0 3 0x100080 kqread resolvd
66630 258146 18725 77 3 0x100092 kqread dhcpleased
97929 195766 18725 77 3 0x100092 kqread dhcpleased
18725 11397 1 0 3 0x80 kqread dhcpleased
10245 382887 0 0 3 0x14200 bored smr
75468 352764 0 0 2 0x14200 zerothread
67481 394300 0 0 3 0x14200 aiodoned aiodoned
7897 80319 0 0 3 0x14200 syncer update
73511 335528 0 0 3 0x14200 cleaner cleaner
20545 115454 0 0 3 0x14200 reaper reaper
24401 48559 0 0 3 0x14200 pgdaemon pagedaemon
12887 241304 0 0 3 0x14200 bored viomb
42768 356795 0 0 3 0x40014200 acpi0 acpi0
27751 522266 0 0 3 0x40014200 idle1
56439 368182 0 0 3 0x14200 bored softnet1
25561 499289 0 0 3 0x14200 bored softnet0
29689 218005 0 0 3 0x14200 bored systqmp
94806 127102 0 0 3 0x14200 bored systq
45993 94108 0 0 3 0x14200 tmoslp softclockmp
3439 455658 0 0 3 0x40014200 tmoslp softclock
89843 32237 0 0 3 0x40014200 idle0
1 976 0 0 3 0x82 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{0}> show all locks
CPU 0:
exclusive mutex &sched_lock r = 0 (0xffffffff83a7a8c0)
#0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1 mtx_enter+0x4b4 sys/kern/kern_lock.c:487
#2 sleep_finish+0x1d6 sys/kern/kern_synch.c:357
#3 sys_futex+0xb90 futex_wait sys/kern/sys_futex.c:306 [inline]
#3 sys_futex+0xb90 sys/kern/sys_futex.c:155
#4 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#4 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
#5 Xsyscall+0x128
Process 57635 (syz-executor) thread 0xffff80003bba7250 (454081)
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff83acc800)
#0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1 syscall+0xaf4 mi_syscall sys/sys/syscall_mi.h:175 [inline]
#1 syscall+0xaf4 sys/arch/amd64/amd64/trap.c:783
#2 Xsyscall+0x128
Process 48912 (syz-executor) thread 0xffff80002a222a70 (30545)
exclusive rrwlock inode r = 0 (0xfffff9805dfb8d80)
#0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1 rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320
#2 rrw_enter+0xc6 sys/kern/kern_rwlock.c:621
#3 VOP_LOCK+0xbd sys/kern/vfs_vops.c:527
#4 vn_lock+0xa4 sys/kern/vfs_vnops.c:576
#5 vget+0x2a2 sys/kern/vfs_subr.c:692
#6 ufs_ihashget+0x185 sys/ufs/ufs/ufs_ihash.c:98
#7 ffs_vget+0x8c sys/ufs/ffs/ffs_vfsops.c:1203
#8 ufs_lookup+0x1a36 sys/ufs/ufs/ufs_lookup.c:478
#9 VOP_LOOKUP+0x6e sys/kern/vfs_vops.c:85
#10 vfs_lookup+0x963 sys/kern/vfs_lookup.c:580
#11 namei+0x7c5 sys/kern/vfs_lookup.c:250
#12 dounlinkat+0xc1 sys/kern/vfs_syscalls.c:1806
#13 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#13 syscall+0xb17 sys/arch/amd64/amd64/trap.c:783
#14 Xsyscall+0x128
exclusive rrwlock inode r = 0 (0xfffff9805dfb8690)
#0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1 rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320
#2 rrw_enter+0xc6 sys/kern/kern_rwlock.c:621
#3 VOP_LOCK+0xbd sys/kern/vfs_vops.c:527
#4 vn_lock+0xa4 sys/kern/vfs_vnops.c:576
#5 vget+0x2a2 sys/kern/vfs_subr.c:692
#6 cache_lookup+0x351 sys/kern/vfs_cache.c:222
#7 ufs_lookup+0x1e3 sys/ufs/ufs/ufs_lookup.c:160
#8 VOP_LOOKUP+0x6e sys/kern/vfs_vops.c:85
#9 vfs_lookup+0x963 sys/kern/vfs_lookup.c:580
#10 namei+0x7c5 sys/kern/vfs_lookup.c:250
#11 dounlinkat+0xc1 sys/kern/vfs_syscalls.c:1806
#12 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#12 syscall+0xb17 sys/arch/amd64/amd64/trap.c:783
#13 Xsyscall+0x128
ddb{0}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 11063 12106K 12411K 166960K 12521 0
pcb 84 16K 16K 166960K 134 0
rtable 251 9K 9K 166960K 387 0
pf 39 18K 25K 166960K 89 0
ifaddr 44 7K 7K 166960K 47 0
ifgroup 60 2K 2K 166960K 62 0
sysctl 4 1K 9K 166960K 9 0
counters 72 37K 37K 166960K 78 0
ioctlops 0 0K 4K 166960K 1521 0
iov 0 0K 16K 166960K 13 0
mount 1 1K 1K 166960K 1 0
log 0 0K 0K 166960K 4 0
vnodes 1415 89K 89K 166960K 1663 0
UFS quota 1 32K 32K 166960K 1 0
UFS mount 5 36K 36K 166960K 5 0
shm 3 5K 9K 166960K 10 0
VM map 2 1K 1K 166960K 2 0
sem 12 0K 0K 166960K 17 0
dirhash 12 2K 2K 166960K 15 0
ACPI 1692 195K 286K 166960K 12470 0
file desc 17 61K 93K 166960K 361 0
sigio 0 0K 0K 166960K 1 0
proc 63 99K 164K 166960K 581 0
subproc 72 4K 4K 166960K 73 0
NFS srvsock 1 0K 0K 166960K 1 0
NFS daemon 1 16K 16K 166960K 1 0
ip_moptions 0 0K 0K 166960K 27 0
in_multi 99 7K 7K 166960K 111 0
ether_multi 1 0K 0K 166960K 4 0
mrt 1 0K 0K 166960K 7 0
ISOFS mount 1 32K 32K 166960K 1 0
MSDOSFS mount 1 16K 16K 166960K 1 0
ttys 61 281K 281K 166960K 61 0
exec 0 0K 1K 166960K 406 0
fusefs mount 1 32K 32K 166960K 1 0
tdb 3 0K 0K 166960K 3 0
VM swap 8 62K 64K 166960K 10 0
UVM amap 228 163K 185K 166960K 5221 0
UVM aobj 16 2K 2K 166960K 18 0
pinsyscall 40 80K 106K 166960K 1547 0
memdesc 1 4K 4K 166960K 1 0
crypto data 1 1K 1K 166960K 1 0
ip6_options 2 0K 0K 166960K 6 0
NDP 13 0K 2K 166960K 30 0
temp 43 9119K 9134K 166960K 19757 0
kqueue 13 20K 28K 166960K 57 0
SYN cache 2 16K 16K 166960K 2 0
ddb{0}> show all pools
Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
plcache 128 28 0 0 1 0 1 1 0 8 0
rtpcb 120 45 0 42 1 0 1 1 0 8 0
rtentry 176 113 0 1 6 0 6 6 0 8 0
unpcb 144 136 0 119 2 0 2 2 0 8 1
syncache 336 4 0 4 1 0 1 1 0 8 1
tcpcb 736 122 0 117 7 0 7 7 0 8 6
arp 136 18 0 0 1 0 1 1 0 8 0
inpcb 328 388 0 310 7 0 7 7 0 8 0
nd6 152 25 0 0 1 0 1 1 0 8 0
pkpcb 40 1 0 1 1 0 1 1 0 8 1
kcovpl 48 8 0 0 1 0 1 1 0 8 0
ppxss 1192 3 0 3 1 0 1 1 0 8 1
pfstscr 40 3 0 1 1 0 1 1 0 8 0
pffrag 232 2 0 0 1 0 1 1 0 482 0
pffrnode 88 2 0 0 1 0 1 1 0 8 0
pffrent 40 3 0 1 1 0 1 1 0 8 0
pfosfp 40 1428 0 1005 5 0 5 5 0 8 0
pfosfpen 112 1428 0 714 21 0 21 21 0 8 0
pfsrclim 320 2 0 2 1 0 1 1 0 8 1
pfanchor 1288 5 0 0 1 0 1 1 0 8 0
pfstitem 24 43 0 0 1 0 1 1 0 8 0
pfstkey 128 45 0 2 2 0 2 2 0 8 0
pfstate 448 43 0 1 5 0 5 5 0 8 0
pfrule 1360 25 0 20 2 1 1 2 0 8 0
art_heap8 4096 2 0 0 2 0 2 2 0 8 0
art_heap4 256 461 0 0 29 0 29 29 0 8 0
art_table 40 463 0 0 5 0 5 5 0 8 0
art_node 32 113 0 11 1 0 1 1 0 8 0
sysvmsgpl 40 1 0 1 1 0 1 1 0 8 1
semupl 112 1 0 1 1 0 1 1 0 8 1
semapl 72 15 0 5 1 0 1 1 0 8 0
shmpl 112 15 0 2 1 0 1 1 0 8 0
dirhash 1024 19 0 2 3 0 3 3 0 8 0
dino2pl 256 1975 0 513 93 0 93 93 0 8 0
ffsino 296 1975 0 513 114 0 114 114 0 8 0
nchpl 144 2484 0 775 64 0 64 64 0 8 0
rtmask 32 2 0 2 1 0 1 1 0 8 1
vnodes 216 2293 0 0 128 0 128 128 0 8 0
namei 1024 8203 0 8203 2 0 2 2 0 8 2
percpumem 16 55 0 3 1 0 1 1 0 8 0
kstatmem 264 31 0 2 2 0 2 2 0 8 0
scxspl 216 8130 0 8129 4 3 1 3 1 8 0
plimitpl 152 43 0 27 1 0 1 1 0 8 0
sigapl 424 688 0 641 7 0 7 7 0 8 1
knotepl 120 542 0 0 17 0 17 17 0 8 0
kqueuepl 224 74 0 65 1 0 1 1 0 8 0
pipepl 344 149 0 121 3 0 3 3 0 8 0
fdescpl 528 671 0 641 3 0 3 3 0 8 0
filepl 160 3112 0 2810 13 0 13 13 0 8 0
lockfpl 104 250 0 243 2 0 2 2 0 8 1
lockfspl 48 119 0 113 1 0 1 1 0 8 0
sessionpl 144 36 0 28 1 0 1 1 0 8 0
pgrppl 48 47 0 31 1 0 1 1 0 8 0
ucredpl 104 330 0 317 1 0 1 1 0 8 0
zombiepl 144 643 0 641 1 0 1 1 0 8 0
processpl 1232 688 0 641 5 0 5 5 0 8 1
procpl 664 1078 0 1024 6 0 6 6 0 8 0
sockpl 752 583 0 485 10 0 10 10 0 8 0
mcl64k 65536 4 0 0 1 0 1 1 0 8 0
mcl16k 16384 3 0 0 1 0 1 1 0 8 0
mcl9k128 9344 1 0 0 1 0 1 1 0 8 0
mcl8k 8192 1 0 0 1 0 1 1 0 8 0
mcl4k 4096 135 0 0 17 0 17 17 0 8 0
mcl2k 2048 22 0 0 3 0 3 3 0 8 0
mextrefs 64 22 0 0 1 0 1 1 0 8 0
mtagpl 96 2 0 0 1 0 1 1 0 8 0
mbufpl 256 181 0 0 11 0 11 11 0 8 0
bufpl 272 2821 0 108 181 0 181 181 0 8 0
anonpl 32 7719 0 0 64 1 63 64 0 247 0
amapchunkpl 152 15987 0 15511 31 0 31 31 0 158 12
amappl16 200 2044 0 2016 19 6 13 15 0 8 8
amappl15 192 2 0 2 1 1 0 1 0 8 0
amappl14 184 443 0 442 1 0 1 1 0 8 0
amappl13 176 130 0 119 1 0 1 1 0 8 0
amappl12 168 933 0 904 2 0 2 2 0 8 0
amappl11 160 3 0 3 1 1 0 1 0 8 0
amappl10 152 65 0 50 1 0 1 1 0 8 0
amappl9 144 274 0 274 1 1 0 1 0 8 0
amappl8 136 105 0 103 1 0 1 1 0 8 0
amappl7 128 146 0 134 1 0 1 1 0 8 0
amappl6 120 156 0 154 1 0 1 1 0 8 0
amappl5 112 97 0 87 1 0 1 1 0 8 0
amappl4 104 299 0 279 1 0 1 1 0 8 0
amappl3 96 2964 0 2854 4 0 4 4 0 8 0
amappl2 88 558 0 497 2 0 2 2 0 8 0
amappl1 80 11514 0 10937 15 0 15 15 0 8 2
amappl 88 4429 0 4269 5 0 5 5 0 92 0
uvmvnodes 80 108 0 0 3 0 3 3 0 8 0
dma4096 4096 1 0 1 1 1 0 1 0 8 0
dma1024 1024 1 0 0 1 0 1 1 0 8 0
dma256 256 6 0 6 1 1 0 1 0 8 0
dma128 128 253 0 253 1 1 0 1 0 8 0
dma64 64 6 0 6 1 1 0 1 0 8 0
dma32 32 7 0 7 1 1 0 1 0 8 0
dma16 16 18 0 17 1 0 1 1 0 8 0
aobjpl 72 17 0 2 1 0 1 1 0 8 0
uaddrrnd 24 671 0 641 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 671 0 641 1 0 1 1 0 8 0
vmmpekpl 168 7334 0 7299 2 0 2 2 0 8 0
vmmpepl 168 51006 0 49157 97 0 97 97 0 357 11
vmsppl 488 670 0 641 5 0 5 5 0 8 1
rwobjpl 80 17230 0 16210 28 1 27 27 0 8 2
pdppl 4096 1349 0 1282 101 30 71 85 0 8 4
pvpl 32 15543 0 0 126 0 126 126 0 265 0
pmappl 256 670 0 641 3 0 3 3 0 8 0
extentpl 40 45 0 27 1 0 1 1 0 8 0
phpool 112 466 0 33 13 0 13 13 0 8 0
ddb{0}> machine ddbcpu 0
Invalid cpu 0
ddb{0}> trace
savectx() at savectx+0xae
end of kernel
end trace frame: 0x768cf77a8b90, count: -1
ddb{0}> machine ddbcpu 1
Stopped at x86_ipi_db+0x27: addq $0x8,%rsp
x86_ipi_db(ffff80002999dff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394
x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27
x86_bus_space_io_write_1(3f8,0,65) at x86_bus_space_io_write_1+0x40 sys/arch/amd64/amd64/bus_space.c:790
comcnputc(800,65) at comcnputc+0x1ab bus_space_barrier sys/dev/ic/com.c:-1 [inline]
comcnputc(800,65) at comcnputc+0x1ab sys/dev/ic/com.c:1268
cnputc(65) at cnputc+0x67 sys/dev/cons.c:218
db_putchar(65) at db_putchar+0x36d sys/ddb/db_output.c:155
kprintf() at kprintf+0x29c5 sys/kern/subr_prf.c:-1
db_printf(ffffffff834ae441) at db_printf+0x9b sys/kern/subr_prf.c:-1
db_ktrap(6,0,ffff80002a2209c0) at db_ktrap+0x1b6 db_printtrap sys/arch/amd64/amd64/db_interface.c:103 [inline]
db_ktrap(6,0,ffff80002a2209c0) at db_ktrap+0x1b6 sys/arch/amd64/amd64/db_interface.c:128
kerntrap(ffff80002a2209c0) at kerntrap+0x243 sys/arch/amd64/amd64/trap.c:519
alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b
dovutimens(ffff80003bba7250,fffff9805cd372d8,ffff80002a220b80) at dovutimens+0x368 sys/kern/vfs_syscalls.c:2690
sys_futimens(ffff80003bba7250,ffff80002a220cd0,ffff80002a220c20) at sys_futimens+0xb3 sys/kern/vfs_syscalls.c:2766
end trace frame: 0xffff80002a220cc0, count: 0
ddb{1}> trace
x86_ipi_db(ffff80002999dff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394
x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27
x86_bus_space_io_write_1(3f8,0,65) at x86_bus_space_io_write_1+0x40 sys/arch/amd64/amd64/bus_space.c:790
comcnputc(800,65) at comcnputc+0x1ab bus_space_barrier sys/dev/ic/com.c:-1 [inline]
comcnputc(800,65) at comcnputc+0x1ab sys/dev/ic/com.c:1268
cnputc(65) at cnputc+0x67 sys/dev/cons.c:218
db_putchar(65) at db_putchar+0x36d sys/ddb/db_output.c:155
kprintf() at kprintf+0x29c5 sys/kern/subr_prf.c:-1
db_printf(ffffffff834ae441) at db_printf+0x9b sys/kern/subr_prf.c:-1
db_ktrap(6,0,ffff80002a2209c0) at db_ktrap+0x1b6 db_printtrap sys/arch/amd64/amd64/db_interface.c:103 [inline]
db_ktrap(6,0,ffff80002a2209c0) at db_ktrap+0x1b6 sys/arch/amd64/amd64/db_interface.c:128
kerntrap(ffff80002a2209c0) at kerntrap+0x243 sys/arch/amd64/amd64/trap.c:519
alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b
dovutimens(ffff80003bba7250,fffff9805cd372d8,ffff80002a220b80) at dovutimens+0x368 sys/kern/vfs_syscalls.c:2690
sys_futimens(ffff80003bba7250,ffff80002a220cd0,ffff80002a220c20) at sys_futimens+0xb3 sys/kern/vfs_syscalls.c:2766
syscall(ffff80002a220cd0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80002a220cd0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x4983e1855d0, count: -16
Struck through repros no longer work on HEAD.